Interpolating telegraph receiving system



Nov. 26, 1935.

e. A. LOCKE INTERPOLATING TELEGRAPB RECEIVING SYSTEM Fileddune 13, 1934M/VENTOR a; A. LDC/(E I WJM ATTORNEY Patented Nov. 26, 1935 UNITEDSTATES- YSTEM INTERPOLATING TELEGRAPH RECEIVIN George A. Locke, GlenwoodLanding, N. Y., assignor to Bell Telephone Laboratories, Incorporated,New York, N. Y., a corporation of New York Application June 13, 193i,Serial No. 730,491

7 Claims.

This invention relates to high speed synchronous telegraph systems inwhich short signal impulses are excessively attenuated and must berebuilt, or regenerated, at a repeating or receive ing station.

, attenuation of high frequency waves on long transmission lines, theshort, or unit length, impulses are sometimes attenuated to a pointwhere they they cannot operate the receiving line relay although longerimpulses are received with ample strength to control the relay.

To make possible signaling under such conditions, synchronous vibratingrelay systems comprising relays, special rings on synchronous receivingdistributors, and sometimes apparatus,

v such as condensers, had been employed. These restore, at the repeatingor the receiving station, the short impulses that had been lostintransmission. The systems heretofore used have usually requiredmultiplex rotary distributors of the continuously rotating type.

According to the present invention the unit length impulses areinterpolated at the receiving or the repeating station by a pair ofpolar relays cooperating with a synchronous rotary distributor of thestart-stop type. The invention is illustrated and described herein asapplied to a terminal repeater operating with a two-wire metalliccircuit between stations. It is understood that the invention is notrestricted to the arrangement shown but may be readily adapted for usewith four-wire metallic circuits, ground return differential, two andone-way polar, voice frequency carrier, and high frequency carriersystems. 7

Referring to the drawing, the terminal repeater illustrated comprises aline, or receiving, relay 5, a repeating and storing relay 2, adistributor D of the synchronous rotary start-stop type, a break relayM, and two transmitting relays t5 and 46. Associated with the repeateris illustrated diagrammatically such portion of a printer P as isrequired to show the circuit of the printer magnet 5%. The distributor Dis provided with two sets of brushes, 1 and 8. These brushes, undercontrol of clutch 25 and a driving motor (not shown), are caused torotate across the face of their associated vibrating segment ring set 5|and distributor control ring set 52, respectively, both brushes makingone complete revolution each time the clutch magnet 9 is energized.

To describe the operation of the repeater circuit in detail let it beassumed that transmission 5 line L is closed at the distant end and thatsignal impulse transmission has not yet started. Under this condition amarking current is flowing over line L and through the line windings ofthe polarized receiving relay l. The direction of flow of 10 thismarking current is such that its magnetic effect on receiving relay lcauses the armature of that relay to be positioned to its right contact.

At this time, prior to the start of signal impulse transmission, thearmature of the polar- 5 ized repeating and storing relay 2 ispositioned to its'right contact and said relay is locked in thatposition in a circuit from negative potential, through resistance 3,right contact and armature of said relay, resistance 5, to groundthrough 0 the upper winding of the relay. With the armature of relay 2on its right contact a circuit is completed from the negative potentialthrough resistance 3, over the right contact and armature of relay 2,conductor 29, vibrating segment 25 30, brush ,1, vibrating segment l0,conductor 53, to ground through the lowermost winding of relay 'I. Thislowermost winding of relay I will hereinafter be referred toas thevibrating winding of that relay. 30

The direction of current flow through the vibrating Winding of relay I,in the circuit just traced, is such that the magnetic force exerted bythe vibrating winding opposes the force being exerted by the'linewindings of the relay and tends to move the armature of the relaytowards its left contact but, since the line winding current is morepowerful than the vibrating winding current, the armature of relay lremains on its right or marking contact in response to the line markingcurrent.

Assume now that the transmission of impulses over the line is started.The first impulse of any impulse series is the start pulse which isspacing, or positive, and of opposite polarity to the marking current.The polarity of the current through the line windings of relay Itherefore is reversed, but before this reversal has completely takenplace, and as soon as the magnetic effect of the preceding marking linecurrent diminishes, the force being exerted by the vibrating windingbecomes effective and causes the armature of relay I to move to the leftcontact of that relay. It

will be obvious that the movement of the armature of relay I thereforeoccurs sooner than if 5 vibrating winding. 7

it had been dependent solely on the magnetic effect of the line windingsof the relay in response to: the line current reversal from marking tospacing.

With the armature of relay I on its left contact a circuit is completedfrom positive pole of battery over the left contact and armature ofrelay left contact and armature of relay I, conductor 28, start segment26, brush 8, start segment 2?, to negative pole of battery, through thewinding of clutch release magnet 9, energizing said magnet whichdisengages latch 24 from clutch 25. Clutch 25 engages brushes I and 8and causes these brushes to rotate across their associated ring sets. Asbrush 8 leaves segments 26 and 2'! the circuit through magnet 9 isopened and the magnet deenergizes and permits latch 24 to restore to itsoriginal position where it will reengage clutch 25 after onerevolution'of brushes '5 and 8. V

As brushes '1 and 8 continue to advance, brush l contacts segments IIand 3| and a circuit is established from the positive pole of battery,over the left contact and armature of relay 44, left contact andarmature of relay I, conductor 28, segment II, brush 1, segment 3|, toground through the lower winding of relay 2. The direction of flow andmagnitude of the current in the lower winding of relay 2 is such that itovercomes the effect of the locking current flowing through the upperwinding of the relay and the armature of relay 2 therefore moves fromitsright to its left contact in agreement with the movement of thearmature of receiving relay I in response to the first incoming impulseover line L. With its armature on the left contact, relay 2 looks inthat position in a circuit from positive pole of battery, throughresistance 6, left contact and armature of relay 2, resistance 5, toground through the upper winding of relay 2. The movement of thearmature of relay 2 from the right to the left contact reverses thepolarity of the potential over its armature and over conductor 29,through the upper windings of relays 44, 45 and 46, through rheostat 47,normally closed printer transmitting contacts 48, normally closedcontacts of key 49, to negative pole of battery, through the winding ofprinter magnet 50. The first incoming impulse or start pulse hastherefore been repeated by relay 2 to the printer P. I

Whenbrush 7 leaves segments II and 3I the circuit through the lowerwinding of relay 2 is opened. Relay 2 remains locked with its armatureon its left contact previously set forth.

As the distributor brushes continue to advance, brush 1 passes over apair of inactivesegments and. th n contacts segments I2 and 32 therebycompleting a circuit from positive pole of bat-v tery, throughresistance 4, left contact and armature of relay 2, conductor 29,segment 32, brush l, segment I2, conductor 53, to ground through thevibrating winding of relay I. p The direction of this current flowthrough the vibrate ing winding of relay l is such that the relayarmature tends to move to its right contact,

Assume now that the second incoming impulse, which is the first signalimpulse, is of the same polarity as the first or start impulse. The

. direction of current flow through the line windings of relay Itherefore remains unchanged and the armature of relay l remains on itsleft contact since the magnetic force exerted by the line windings isgreater than that exerted by the When brush 7 contacts segments I3 and33 2.

circuit is completed from positive pole of battery, over the leftcontacts and armatures of relays 44 and I, conductor 23, segment I3,brush 1, segment 33 to ground through the lower winding of relay 2.Since relay 2 has previously locked 5 with its armature on its leftcontact no change in the position of its armature occurs and thepolarity of the potential connected to the winding of printer magnet 58,over the circuit previously traced, remains unchanged. 10 The circuitthrough the lower winding of relay 2 is opened as brush 7! leavessegments I3 and 33. The armature of relay 2 remains on its left contactsince the relay is held in that position by the current flowing throughits upper winding 15 as hereinbefore set forth. Brush 7, after passingover a pair of inactive segments, next contacts segments I4 and 34thereby completing the circuit from positive potential throughresistance 6, over the aforementioned brush and segments, to 20 groundthrough the vibrating winding of relay I. The resulting current flowthrough the vibrating Winding is in the direction which causes themagnetic force exerted by that winding to oppose the force exerted bythe flow of spacing cur- 2 rent through the line windings of relay I.Let it now be assumed that the third impulse incoming over line L is amarking impulse. The current flow through the line windings of relay Iwill therefore reverse in response to the change 30 from spacing tomarking polarity. As the effect of the magnetic force which was beingmaintained in the line windings of relay I by the preceding spacingcurrent diminishes, the opposing force exerted by the vibrating windingpredomi- 35 nates and the armature of relay I moves to the rightcontact. The positioning of the armature of relay I is therefore notdependent upon a reverse in the line winding magnetic force but iseffected instead by the vibrating winding force 40 which becomeseffective as the existing line winding force diminishes upon a linecurrent reversal. In the foregoing manner, a unit length impulse, whichmay have been attenuated to a degree where it is of insufficient lengthto produce a line 45 winding magnetic force capable of changing theposition of the armature of relay I, is interpolated by the action ofthe vibrating winding of relay 1 in conjunction with the vibrating ringset 5| and brush 1 of distributor D, and the 50' vibrating winding ofrelay I to interpolate the 55 third impulse as just set forth, thepolarity of the potential on segments II, I3, I5, I'I, I9, 2! and 23, inthe circuit over conductor 28 and the armature of relay I, changes frompositive to negative. After leaving segments I l and 34, no therebyopening the circuit through the vibrating winding of relay I, brush 1contacts segments I5 and 35 and completes a circuit from negative poleof battery, over segment I5, over brush I and segment 35, to groundthrough the lower 5 winding of relay 2. The resultant current flowthrough the lower winding of relay 2 is greater than, and in theopposite direction to, the locking current flowing through the upperwinding of that relay. The armature of relay 2 there- 70 fore moves fromthe left to the right contact in agreement with the position of thearmature of relay I. Negative potential through resistance 3, over theright contact and armature of relay 2, and through resistance 5 toground through the 75 upper winding of relay 2 locks that relay in itsright or marking position. The change in the polarity of the potentialon conductor 29, by the repositioning of the armature of relay 2,reverses the polarity of the potential connected to the winding ofprinter magnet 59 thereby repeating the third incoming impulse toprinter P.

As the brushes of distributor D continue to ad Vance through theremainder of their complete revolution, the subsequent impulses incomingover line L are repeated to the printer P in a manner similar to thathereinbefore set forth for the first three impulses. Brush 1, incontacting segments It and 36, I8 and 38, 20 and 40, and 22 and Q2,completes the circuit through the vibrating winding of relay Undercontrol of relay 2, which determines the polarity of the potentialconnected to segments 36, 38, 40 and 42, the direction of the flow ofcurrent through the vibrating winding of relay l, upon each of theaforementioned closures through that winding,

is such that the vibrating winding magnetic force at all times opposesthe line winding magnetic force set up by the line current of thepreceding impulse; The armature of the storing and repeating relay 2 ispositioned, to agree with the position of the armature of receivingrelay l for the fourth, fifth, sixth and seventh, or stop, impulses whenbrush 1 completes the circuit over segment pairs l1 and 31., i9 and 39,2| and GI, and 23 and 43, successively. Upon each change in the positionof the armature of relay 2, the polarity of the potential applied to thevibrating winding of relay l and to the winding of printer magnet 50 isreversed to correspond with the polarity of the incoming impulse.

The final impulse of each character impulse series, known as the stopimpulse, is always a marking impulse and the armature of relay I alwaysmoves to or remains on its right contact at the conclusion of any seriesof incoming impulses. As brush 1 passes over segments 23 and t3 thearmature of relay 2 is positioned to its right contact by the directionof the flow of current through its lower winding in the circuit to thenegative potential over. conductor 28 and over the armature and rightcontact of relay I. The brushes of distributor D have now made acomplete revolution and the released latch 24 re-engages clutch 25thereby causing the distributor brushes to come to rest, brush 1 incontact with segments I0 and 30, and brush 8 traced through resistance3, over the right contact and armature of relay 2, segment 30, brush 1,segment Ill, and conductor 53. The winding of clutch release magnet 9 isagain connected to the armature of relay 1 in the circuit over segment21, brush 8, segment 26, and conductor 28. The repeater circuit is nowin the identical condition set forth at the outset of this descriptionof the point prior to the start of the transmission of the first seriesof incoming impulses. For each succeeding series of signal impulses thefirst, or start, impulse operates clutch release magnet 9 which causesthe distributor brushes 1 and 8, under control of clutch 25, to make onecomplete revolution. Relays l and 2, in conjunction with the segments ofdistributor ring set 5! and brush 7, interpolate all unit length signalimpulses and repeat the incoming signal impulses to printer P' From theforegoing description it will be obvious that, since unit lengthimpulses are locally regenerated and interpolated, an increase in thespeed of impulse transmission or an increase in the length of thetransmission line, may be realized by the use of this invention due tothe fact that the unit length impulses can be shortened or attenuatedbeyond the point where they could effectively position the armature ofreceiving relay i solely by the magnetic force which they produce in theline windings of that relay.

What is claimed is:

1. In a telegraph system, the combination of a transmission circuit, asource of current for transmitting groups of impulses over said circuit,a relay comprising a line winding for receiving the impulses from saidcircuit and a second winding, an armature and current supply contactscooperating therewith, a local circuit including said second windingarranged when energized to produce' amagnetic effect on said armaturesuf- .ficient to cause the movement thereof, electroergization of saidelectromagnetic means and said local circuit winding whereby saidarmature is caused to reverse its position, and other means responsiveto the energization of said line winding only by the first impulse ofeach group received over said transmission circuit for starting saidrotatably operated means.

2. In combination with a telegraph system, a receiving relay comprisinga line Winding, an armature, current supply contacts cooperatingtherewith, local circuit electromagnetic means arranged to produce amagnetic effect on said armature sufiicient to cause the movementthereof, a relay serving to control the energization of said localcircuit, electromagnetic means, and a' start-stop rotary devicecooperating with said relay for energizing said local circuitelectromagnetic means.

3. A system for receiving combinations of start, intermediate and stopimpulses in which incoming signal impulses of unit length not receivedin effective amplitudes, are regenerated and incoming signal impulses ofplural unit lengths are received in effective amplitudes, characterizedin this that a line relay and a storing relay are alternately efiectivewhen unit length impulses are being received to operate each otherthrough an intermittently rotatable device, said device being arrangedto start to rotate through one revolution only in response to the firstimpulse of an incoming signal code combination and stop when the lastimpulse of said combination is received.

4. A system according to claim 3 wherein the intermittently rotatabledevice is a start-stop rotary distributor comprising two ring sets, onefor controlling the starting and'the stopping of rotation of said deviceand the other for causing said line and said storing relay toalternately operate during the interval that the device is r0- tatingthrough one revolution when incoming unit length signal impulses arebeing received.

5. A system comprising a circuit for receiving incoming signalcombinations of start, intermediate and stop impulses, a line relayhaving a plurality of windings for receiving said signal combinationsfrom said circuit, an armature and contact for said line relay, anintermittently rotatable device comprising a plurality of receivingdistributor ring sets and a rotatable member therefore, an electromagnetfor controlling the rotation of said member, a storing relay, anarmature and contact for said storing relay, a normally deenergizedcircuit comprising a source of potential, the armature and contact ofsaid line relay and a plurality of parallel paths, one extending throughthe first of said ring sets and the Winding of said electromagnet, andthe other of said paths extending through the second of said ring setsand a Winding of said storing relay, said other of said paths providingmeans for alternately energizing and deenergizing said circuit duringrotation of said device, and a normally energized circuit comprising asource of potential, the armature and contact of said storing relay, thesecond of said ring sets and a winding of said line relay, said normallyenergized circuit having a plurality of paths over which it may bealternately deenergized and energized during rotation of said device.

6. A start-stop receiving system for receiving combinations of start,code and stop impulses, in which unit impulses following a start impulseare not received in effective amplitude, comprising a line circuit, alocal circuit, a line relay having line circuit windings and. a localcircuit Winding, said relay being ineffective in response to incomingcode impulses of unit length but effective in response to incoming codeimpulses of two or more unit lengths, a start-stop rotary distributorand a storing relay connected in said local circuit and a printercontrolled by said storing relay, said distributor being arranged torotate through one revolution in response to the start impulse and toprovide through its rotation, for said line. relay and said storingrelay to alternately control the operation of each other duringintervals when unit length impulses are

